Telephone receiver



J.' M. WILSON TELEPHONE RECEIVER Filed Sept. 18, 1922 April 3,'-1928.- v 1,665,078

f 41 mam A T roHNgY.

Patented Apr. 3, 1928.

JAMES M. wiLsolL-ol NEWARK, NEW- JERSEY, essienon T0 AMrLIToNE COMPANY, me, on NEW YGBK, 1v. A CORPORATION on NEW YORK.

T L-assess RECEIVER.

m lic t on filed'septembr 1s, 1922. Serial n 588,808.

The object or" my invention is to improve the construction and'operation of telephone receivers, and particularly those used in radio-telephony, whereby the sound reception is materially clarified, muffling and overtones eliminated and sound volume greatly increased, and it consists of plae a secondary diaphragm in close uxtaposition' to the primary diaphra 'm, and separated therefrom by a noi1-metallic or elastic element located between their centers; so that when the two diaphragms are placed under a de n re' e ompr ve, as y rewi'ng down the cover cap, the cei'i't-ers of the diaphragms will be flexed out of their normal planes. It has been hitherto proposed to connect apair of marginally"clamped diaphragms with a rigid strut located at their centers; but I lindthat such a construction serves to magnify and emphasize some of'tl ie defects of a single diaphragm, and to impair the transmission of sound waves. \Vhereas, the inclusion of the slightly elastic or nonmetallic element or member" under the com.- pression as hereinafter indicated, softens the metallic ring,'.-eliminates overtonesand materially increases the volume of sound'transmission.

In the accompanying drawing, I have shown only so much of well l'rnown form of receiver as may be necessary. to gain a full understanding of my improven'ient. In the drawing Fig. l is a side elevation, partly in section of a receiver with my improvement included therein.

Fig. is a plan of the secondary diaphragm.

Fig. 8 is a similar View of the primary diaphragm.

Fig. 4 is a diagrammatic section of the combined diaphragms showing their relative locations with respect to th'e'receiv'er poles, but withoutcompression.

F'g. 51s a similar View, but showing the positions cram two diaphragms when under compression.

Fig. 6 is a' side elevation partly iii section of a. modified form ofreceiver'.

Figs. 7 and 8' are respectively top and bottom plans of the two'diaphragms shown in Fig. 6'.

Figs. 9 and 10 are respectively modified forms Qf'illl separating elementpermanently connected to the secondary diaphragm.

Similar reference numerals refer to like parts throughout the specification and drawmg. I

The receiver body, or cup 1 die mz g'net system 2 and the talking circuit leads 3 are of the usual or off any referred construetion, andoperate in the us 'ial manner. The cover cap 451's screweddown upon the thread ed cup flange 5, and maybe held in any adjusted position by the 'srn'all set screw 6, passing through the cap flange and he ring upon the cup flange. The cap 4: hasjtlie ii ternal'ledge' or shoulder 7, whichb'earsj upon the margin of the diaphragm. Allofthese parts are of the usual con rufc tioii, except that ap flange. is ma e n W atdQ6Per so asto provide for the extra depth of the two diaphragms when in place,

T e r t ll" diaph agm 8 Slight y 6 1- vexe'd, as shown in 4, andhas a slight pro ection 9 its center, wh ch ay he made by a center punch. In asseinhling the dia phra'gm' 8' rests upon the upper edge 01 cup 1 with its onvex side uppermost. The secondary diaphragm 1O is a plane disk, and may be either metallic or non-metallic. Excellent results have been obtained with secondary diaphragms made of mica, brass, aluminum, bronze, copper and thin sheet steel, among the metallic elements, aiid glass,

cc lllOid, parchment, and sliellac-impreg-..

nated' paper amongthe nommetallic elements. So that the material is not important so 1011 as it is of the proper thickness and has the requisite elasticity. At the cen ter oi the secondary diaphragm a small cylindrically headed'rivet 11, upon which the short section of tubing 12 is placed and held by friction. The secondary diaphragm is then placed upon the primary diaphragm 8, witli the tube separator 12 over the piroje'ctio'ni), which serves to center the second.- ary, and finally the 4 screwed down upon the cup l'with the ledge hearingupon and compressing the margin of the diaphragm. As the cap et'is screwed down, the convexity of the primary diaphragm 8 is reduced and its center is pressedinto close. proximity to the pics of the magnet 2, and at the same time the secondary diaphragm 10 is converted, as shown in Figs. 1 and The degree ofthis compression of thediaphragms is determined by the proximity ofthe center of the primary diaphragm to the magnet poles, which should he such that with its maximum vibration the dia phragm should not actually contact the poles. In some cases, the convexity of the primary diaphra m is reduced to nothing, that is, the diaphragm is a plane disk; the pressure may even go ,further and depress the center until the convexity is reduced to a slight concavity, so long 'as the contact conditions are preserved. The adjustment is based upon the results obtained, the cap being screwed to that position where the'greatest volume and clearestsound is transmitted.

In Fig. 6, I have shown a slight modification of the receiver cup 1 and cap 1, to provide for a secondary diaphragm of larger diameter than the primary diaphragm 8. The screw-threaded cup flange 5 is made larger to receive a correspondingly enlarged cap 1, within which is the ledge 7, bearing upon the margin of the enlarged secondary diaphragm 10. A slight recess 13 is pro-- vided in the upper inner edge of the cup to receive the primary diaphragm 8; the separating element 12 is located and secured in the same manner as heretofore described, and the adjustment is accomplished in the same manner.

I have found in practice that slightly better results are obtained in the way of clarity and volume, when the secondary diaphragm is made ofsome of the non-metallic materials and ofa larger diameter than with both diaphragms of the same diameter. i

The separator12 or 12 may be attached .to the secondary diaphragm in the manner above described, or it mayconsistof a small cup 14, with the rivet 15 passing through its bottom and secured to tie center of the diaphragm, as shown in Fig. 9. Or it may be in the form of a rivet with a covered head, as shown at 16 in Fig. 10. lVhen a slightly elastic or non-metallic trace of that metallic resonance so frequently present with and in a single receiver diaphragm seems to be eliminated, and the tone is clear and of increased volume, and the ab- 7 sence of muffling and overtones is at om apparent. 1

By the construction shown and described,

I am able to accomplish very much improved results in the way of sound reception, even more than the simplicity of the device would seem to warrant or indicate.

Itlwillbenoted that the primary and secondary diaphragms are confined between the ledge 7 and the upper edge of the cup 1, with the member 12separating them at the center, leaving the adjacent'faces of the diaphragms free from compression. In the usual single-diaphragm receiver, it is customary to, compress or confine the margin of the diaphragm between the ledge and the upper edge of the cup. This necessarily impairs the freedom of vibrational movement separator is used, all

of the diaphragm, for it permits the flexing of the diaphragm only within the unconfined area; that is, within the confined margin. This clamping of the margin must therefore produce undue mechanical stresses in the diaphragm, with a resulting damping of sound vibration.

The material from which the separator or spacing member 12, 12', 14, or 16, is made may be either soft or hard rubber, fiber, wood, or any non-metallic substance, all of which may be considered as elastic, or slightly yielding under pressure. p,

I am aware that it has been proposed to provide a receiver with two diaphragms held apart by a rigid spacing member, but I believe that I amthe first to use a plane secondarynnd a convex. primary diaphragm, with a non-metallic or elastic spacing member between them, together with means for flexing'the secondary into convex form and ineansupon said cup and cap for PIGSSlIlg.

the circumferences of said diaphragms toward each other, whereby the convexity of said primary diaphragm is reduced and said secondary diaphragm ismade convex.

2. Ina telephone receiver, the combination of a plane diaphragm, a convex dia phragm, a spacing member between the centers of said diaphragms,and means for applying of said diaphragms at their margins to flex the same toward each other, wl.1 ereby said plane diaphragm is made convex and said convex 'diapl'iragm is made plane.

3. In a, telephone receiver, the combination of aplane diaphragm, a convex diaphragm, and a spacing member between their centers, and means pressing their margins together to convex said plane diaphragm and reduce the convexity of said convex diaphragm,

4. In a telephone receiver, the combination of a receiver cup and a cover cap therefor, with a convex primary diaphragm, a plane secondary diaphragm, a spacing member between the centers of said. diaphragms, and means upon said cup and cap for pressing the circumferences of said diaphragms toward each otherto change said secondary diaphragm to convex and reduce the convexlty of sa1d primary diaphragm.

pressure upon the non-adjacent faces 1 5. In a telephone receiver, the combination of a pair of diaphragms of different diameters, a spacing member located between the centers of said diaphragms, and means applied to the circumferences of said diaphragms to flex the same toward each other.

6. In a telephone receiver, the combinatron of a receiver cup and a cover cap therefor, a primary diaphragm and a secondary diaphragm, a spacing member located centrally 0t and yieldingly separating said diaphragms, and means for clamping said dia phragms between said cap and cup whereby said diaphragms are flexed from their normal planes.

7. in a telephone receiver, the combination of a primary diaphragm and a secondary diaphragm a spacing men'iber yieldingly separating said diaphragms at their centers, and means for placing the margins of said diaphragms under slight compression to flex them from their normal planes.

8. In a telephone receiver, the combination of a pair of juxtaposed diaphragms, a non-metallic spacing member located between the centers of said diaphragms, a receiver cup and a cover cap therefor, and means upon said cup and cap bearing upon the non-adjacent margins of said diaphragms for flexing the same toward each other.

9. An instrument for translating electrical undultations into sound vibrations compr.is ing in combination, a pair of centrally spaced diaphragms, means engaging said diaphragms adjacent their peripheries and flexing said diaphragms, the distance between the center 01" one of said diaphragms and said last named means being greater than the corresponding distance between the center ot' the other diaphragm and the said last named means, and means including an electromagnet for vibrating said diaphragm, one of said diaphragms being located. be tween said electron'iagnet and the other diaphragm.

lU. A device of the class described coinprising in combination, a casing, a cap adjustable toward and away from said casing, an electromagnet mounted in said casing, and a pair of centrally spaced diaphragms mounted between said electromagnet and cap, said diaphragms being of different eli'ective diameters, and means upon said casing and caps for engaging the non-adjacent margins oi said diaphragms and flexing the same toward each other upon movement of said cap toward said casing.

11. A device of theclass described comprising in combination, a casing, a cap adjustable toward and away from said casing, an clectromagnet mounted in said casing, and a pair of centrally spaced diaphragms mounted between said electromagnet and cap, said diaphragms being of different e'ti'ective diameters, means upon said casing and cap "for engaging the non-adjacent margins of said diaphragms and flexing the same toward each other uponmovement of said cap'toi'vard said casing, and means torlocking the cap and casing in various positions of relative adjustment.

12. An instrument. for translating electrical. undultations into sound vibrations comprising in combination, a disc-shaped primary diaphragm and an electromagnet of which said diaphragm constitutes the armature, a secondary diaphragm located on the side of said primary diaphragm remote from said electromagnet, means spacing said diaphragms substantially at their centers, and means engaging said diaphragms adjacent their peripheries tor flexing said diaphragms toward each other.

13. The instrument set forth in claim 12 in which the secondary diaphragm is constructed of a diiierent material than that of the primary diaphragm.

1st. The instrument set forth in claim 12 in which the secondary diaphragm is constructed oi non-metallic material.

15. The instrument set forth in claim 12 in which the two diaphragms are of different effective diameters.

16. The instrument set forth in claim 12 in which the secondary diaphragm is con-- JAMES M. l VILSON.

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